<!DOCTYPE html>
<html>
  <head lang="en">
    <meta charset="UTF-8" />
    <title></title>
    <style>
      * {
        padding: 0;
        margin: 0;
      }

      .wrap {
        width: 300px;
        margin: 100px auto 0;
      }

      table {
        border-collapse: collapse;
        border-spacing: 0;
        border: 1px solid #c0c0c0;
        width: 300px;
      }

      th,
      td {
        border: 1px solid #d0d0d0;
        color: #404060;
        padding: 10px;
      }

      th {
        background-color: #09c;
        font: bold 16px '微软雅黑';
        color: #fff;
      }

      td {
        font: 14px '微软雅黑';
      }

      tbody tr {
        background-color: #f0f0f0;
      }

      tbody tr:hover {
        cursor: pointer;
        background-color: #fafafa;
      }
    </style>
  </head>

  <body>
    <div class="wrap">
      <table>
        <thead>
          <tr>
            <th>
              <input type="checkbox" id="j_cbAll" />
            </th>
            <th>商品</th>
            <th>价钱</th>
          </tr>
        </thead>
        <tbody id="j_tb">
          <tr>
            <td>
              <input type="checkbox" />
            </td>
            <td>iPhone8</td>
            <td>8000</td>
          </tr>
          <tr>
            <td>
              <input type="checkbox" />
            </td>
            <td>iPad Pro</td>
            <td>5000</td>
          </tr>
          <tr>
            <td>
              <input type="checkbox" />
            </td>
            <td>iPad Air</td>
            <td>2000</td>
          </tr>
          <tr>
            <td>
              <input type="checkbox" />
            </td>
            <td>Apple Watch</td>
            <td>2000</td>
          </tr>
        </tbody>
      </table>
    </div>
    <script>
      var quan = document.querySelector('#j_cbAll')
      var xiaos = document.querySelectorAll('#j_tb input')
      quan.onclick = function () {
        for (var i = 0; i < xiaos.length; i++) {
          xiaos[i].checked = this.checked
        }
      }
      for (var i = 0; i < xiaos.length; i++) {
        xiaos[i].onclick = function () {
          for (var i = 0; i < xiaos.length; i++) {
            var flag = true
            if (!xiaos[i].checked) {
              flag = false
              break
            }
          }
          quan.checked = flag
        }
      }
    </script>
  </body>
</html>
